<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            /* 因为图片是白色的所以需要另外给个背景颜色才可以显示出来 */
            background-color: #333;
        }

        .map {
            position: relative;
            width: 747px;
            height: 617px;
            background: url(../images/map.png) no-repeat;
            margin: 0 auto;

        }

        .city {
            position: absolute;
            top: 228px;
            right: 191px;
        }

        .dotton {
            width: 8px;
            height: 8px;
            background-color: #0099ff;
            border-radius: 50%;
        }

        .map div[class^="pulse"] {
            position: absolute;
            /* 这个边偏移是参考city来定位的  但又因为city没有宽高 但他下一级的botton有 所以就是取botton宽高的50% */
            top: 50%;
            left: 50%;
/* 如果遇到给了 transform:translate: (-50%,-50%);却没有水平垂直居中显示 先试试清除该元素的内外边距 */

            transform: translate(-50%, -50%);
            width: 8px;
            height: 8px;
            box-shadow: 0 0 12px #0099ff;
            border-radius: 50%;
            animation: pulse 1.2s  linear infinite ;
        }
        .city div.pulse2 {
            animation-delay: 0.4s;
        }
        .city div.pulse3 {
            animation-delay: 0.8s;
        }

        @keyframes pulse {
            0% {}

            70% {
                width: 40px;
                height: 40px;
                opacity: 1;
            }

            100% {
                width: 70px;
                height: 70px;
                opacity: 0;
            }
        }
    </style>
</head>

<body>
    <div class="map">
        <div class="city">
            <div class="dotton"></div>
            <div class="pulse1"></div>
            <div class="pulse2"></div>
            <div class="pulse3"></div>
        </div>

    </div>
</body>

</html>